Influence of Thermal Cracking on Propylene Selectivity in Catalytic Propane Dehydrogenation Using SnOx–SiO2 Catalyst

Propane dehydrogenation is crucial for propylene production, and silica-supported tin oxide (SnOx-SiO2) emerges as an economical, low-coking catalyst. This study delves into the impact of thermal cracking on propylene selectivity during catalytic propane dehydrogenation using SnOx–SiO2. Catalysts with varied percent loadings were synthesized via the sol–gel method. The experiment manipulated active sites (0.025–0.263 g of SnO2), temperature (550–650 °C), and feed composition (15:0 and 2:13 mL/min of C3H8:N2). Results revealed a positive correlation between the thermal cracking to total conversion (THC/TC) and cracking to propane dehydrogenation (cracking/PDH) ratio. Methane production dramatically depends on operating conditions, confirming that thermal cracking has a greater influence on side products than the catalyst. Propylene from catalytic propane dehydrogenation helped mitigate the thermal cracking slightly. Ethane, ethylene, and propylene production indicated ethane generation through ethylene hydrogenation in a thermal cracking chain reaction, utilizing hydrogen from propane dehydrogenation. This study proposes thermal cracking as a significant side reaction during SnOx–SiO2-catalyzed propane dehydrogenation, impacting propylene selectivity. Rigorous control of operating conditions and active sites is vital to minimize thermal cracking when using this catalyst.